Thermoplastic resin composition, method of preparing the same, and molded article manufactured using the same

A method of preparing a thermoplastic resin composition, comprising kneading and extruding, at 180 to 300° C. and 80 to 400 rpm:

• an alkyl (meth)acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A) comprising:
• a polymer seed comprising:
• 51 to 77% by weight of a first alkyl (meth)acrylate, and
• 23 to 49% by weight of a first aromatic vinyl compound,
• a rubber core surrounding the polymer seed and comprising:
• 78 to 90% by weight of a first alkyl acrylate, and
• 10 to 22% by weight of a second aromatic vinyl compound, and
• a graft shell surrounding the rubber core and comprising:
• 65 to 80% by weight of a third aromatic vinyl compound,
• 14 to 25% by weight of a first vinyl cyanide compound, and
• 3 to 15% by weight of a second alkyl acrylate;
• and
• a non-graft copolymer (B) comprising:
• a second alkyl (meth)acrylate,
• an alkyl-substituted styrene-based compound, and
• a second vinyl cyanide compound,
• wherein the graft copolymer (A) satisfies both Equations 1 and 2:
• 200
• ≤
• 2
• *
• r
• ⁢
• 2
• ≤
• 300
• Equation
• ⁢
• 1
• 25
• ≤
• r
• ⁢
• 2
• -
• r
• ⁢
• 1
• ≤
• 45
• ,
• Equation
• ⁢
• 2
• wherein r1 represents an average radius (nm) from a center of the graft copolymer to an exterior point of the polymer seed, and r2 represents an average radius (nm) from the center of the graft copolymer to an exterior point of the rubber core,
• wherein the alkyl-substituted styrene-based compound comprises one or more selected from the group consisting of α-methyl styrene, ρ-methyl styrene, o-ethyl styrene, m-ethyl styrene, ρ-ethyl styrene, ρ-t-butyl styrene, and 2,4-dimethyl styrene.